title: Present and future of glass-ionomers and calcium-silicate cements as bioactive materials in dentistry: biophotonics-based interfacial analyses in health and disease.
abstract: OBJECTIVE
  Since their introduction, calcium silicate cements have primarily found use as endodontic sealers, due to long setting times. While similar in chemistry, recent variations such as constituent proportions, purities and manufacturing processes mandate a critical understanding of service behavior differences of the new coronal restorative material variants. Of particular relevance to minimally invasive philosophies is the potential for ion supply, from initial hydration to mature set in dental cements. They may be capable of supporting repair and remineralization of dentin left after decay and cavity preparation, following the concepts of ion exchange from glass ionomers.
  
  
  METHODS
  This paper reviews the underlying chemistry and interactions of glass ionomer and calcium silicate cements, with dental tissues, concentrating on dentin-restoration interface reactions. We additionally demonstrate a new optical technique, based around high resolution deep tissue, two-photon fluorescence and lifetime imaging, which allows monitoring of undisturbed cement-dentin interface samples behavior over time.
  
  
  RESULTS
  The local bioactivity of the calcium-silicate based materials has been shown to produce mineralization within the subjacent dentin substrate, extending deep within the tissues. This suggests that the local ion-rich alkaline environment may be more favorable to mineral repair and re-construction, compared with the acidic environs of comparable glass ionomer based materials.
  
  
  CONCLUSIONS
  The advantages of this potential re-mineralization phenomenon for minimally invasive management of carious dentin are self-evident. There is a clear need to improve the bioactivity of restorative dental materials and these calcium silicate cement systems offer exciting possibilities in realizing this goal.
authors.affiliation: King's College London Dental Institute, Biomaterials, Biomimetics & Biophotonics (B(3)), Floor 17, Guy's Tower Wing, Guy's Hospital, London Bridge SE1 9RT, United Kingdom. Electronic address: timothy.f.watson@kcl.ac.uk.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Watson
authors.affiliation: King's College London Dental Institute, Biomaterials, Biomimetics & Biophotonics (B(3)), Floor 17, Guy's Tower Wing, Guy's Hospital, London Bridge SE1 9RT, United Kingdom.
authors.forename: Amre R
authors.initials: AR
authors.lastname: Atmeh
authors.affiliation: King's College London Dental Institute, Biomaterials, Biomimetics & Biophotonics (B(3)), Floor 17, Guy's Tower Wing, Guy's Hospital, London Bridge SE1 9RT, United Kingdom.
authors.forename: Shara
authors.initials: S
authors.lastname: Sajini
authors.affiliation: King's College London Dental Institute, Biomaterials, Biomimetics & Biophotonics (B(3)), Floor 17, Guy's Tower Wing, Guy's Hospital, London Bridge SE1 9RT, United Kingdom.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cook
authors.affiliation: King's College London Dental Institute, Biomaterials, Biomimetics & Biophotonics (B(3)), Floor 17, Guy's Tower Wing, Guy's Hospital, London Bridge SE1 9RT, United Kingdom.
authors.forename: Frederic
authors.initials: F
authors.lastname: Festy
mesh_terms: D000180:Acrylic Resins; D017610:Calcium Compounds / Q000008:administration & dosage*; D003738:Dental Cements; D006801:Humans; D017640:Silicates / Q000008:administration & dosage*; D012822:Silicon Dioxide; D014089:Tooth Remineralization
chemical_list: D000180:Acrylic Resins; D017610:Calcium Compounds; D003738:Dental Cements; D017640:Silicates; C015897:glass ionomer; D012822:Silicon Dioxide; C031293:calcium silicate
keywords: Bioactivity; Biophotonic imaging; Calcium silicate; Caries; Cements; Glass ionomer; Remineralization